Japanese Patent Laying-Open No. 4-340330 (PTD 1) discloses a quick charger that charges a battery by a DC power source circuit for stepping down AC power and converting the AC power into DC power. In this quick charger, single-phase AC power from a single-phase AC power source is stepped down by a single-phase transformer, and DC power rectified by a rectification bridge is supplied to the battery (refer to PTD 1).